feat: remove Establishment dates for some countries

Some countries have complicated history and may have multiple
establishment dates.

It may be controversial to choose a specific establishment date for some
of them, and especially since I personally don't know about the
intricate policits surrounding each of the 200 countries I'll remove
them.

Closes #19
Closes #18
Closes #7

Author: nik-rev

src/country_format.rs

@@ -393,7 +393,8 @@ pub fn format_country(
             |c| c.neighbours.clone(),
         )),
         established_date: (!args.no_established_date)
-            .then_some(extra_country_data::established_date(gen_country)),
+            .then(|| extra_country_data::established_date(gen_country))
+            .flatten(),
         iso_codes: (!args.no_iso_codes).then_some(country.map_or_else(
             || {
                 (

src/extra_country_data.rs

@@ -85,8 +85,8 @@ pub fn currency_position(country: Country) -> CurrencyPosition {
 
 /// The date when each country was established
 #[allow(clippy::match_same_arms, reason = "readability")]
-pub fn established_date(country: Country) -> &'static str {
-    match country {
+pub fn established_date(country: Country) -> Option<&'static str> {
+    Some(match country {
         Country::Afghanistan => "August 19, 1919",
         Country::AlandIslands => "December 6, 1917",
         Country::Albania => "November 28, 1912",
@@ -264,7 +264,7 @@ pub fn established_date(country: Country) -> &'static str {
         Country::Peru => "July 28, 1821",
         Country::Philippines => "June 12, 1898",
         Country::PitcairnIslands => "January 15, 1790",
-        Country::Poland => "November 11, 1918",
+        Country::Poland => return None,
         Country::Portugal => "October 5, 1143",
         Country::PuertoRico => "July 25, 1952",
         Country::Qatar => "September 3, 1971",
@@ -297,7 +297,7 @@ pub fn established_date(country: Country) -> &'static str {
         Country::SouthGeorgia => "May 3, 1985",
         Country::SouthKorea => "August 15, 1948",
         Country::SouthSudan => "July 9, 2011",
-        Country::Spain => "December 6, 1978",
+        Country::Spain => return None,
         Country::SriLanka => "February 4, 1948",
         Country::Sudan => "January 1, 1956",
         Country::Suriname => "November 25, 1975",
@@ -337,5 +337,5 @@ pub fn established_date(country: Country) -> &'static str {
         Country::Yemen => "May 22, 1990",
         Country::Zambia => "October 24, 1964",
         Country::Zimbabwe => "April 18, 1980",
-    }
+    })
 }

src/generated_country_data.rs

@@ -4,9 +4,6 @@
 #![allow(clippy::should_implement_trait)]
 #![allow(clippy::needless_arbitrary_self_type)]
 
-pub mod extras;
-pub use extras::*;
-
 #[derive(Eq, PartialEq, Copy, Clone, Ord, PartialOrd, Debug, clap::ValueEnum)]
 #[clap(rename_all = "PascalCase")]
 pub enum Country {